Thin film magnetic recording media

Abstract

A thin film magnetic recording disc is provided wherein the magnetic layer is an alloy of cobalt and platinum disposed on a chromium layer. A barrier layer of chromium is formed on the cobalt-platinum film and a wear layer of an oxide of cobalt is provided on the barrier layer. The platinum content in the magnetic film is varied so as to provide a magnetic film with a desired coercivity which is significantly less dependent upon film thickness. This permits the cobalt-platinum film thickness to be adjusted to meet a wide range of recording system design parameters. The coercivity of the magnetic film may be determined primarily by the amount of platinum in the alloy and the saturation magnetization-thickness product of the film is determined primarily by the film thickness.

What is claimed is: 
     
       1. A magnetic film of an alloy of cobalt and platinum formed on a layer of chromium and containing from about 1 to about 20 atomic percent platinum in which the coercivity of said film is determined primarily by the percentage of platinum in said alloy and the saturation magnetization-thickness product of said film is determined primarily by the thickness thereof. 
     
     
       2. A magnetic recording disc comprising a substrate member of aluminum having a surface layer thereon of an alloy of nickel and phosphorus; a layer of chromium disposed on said surface layer; a magnetic layer of cobalt and platinum containing from about 1 to about 20 atomic percent platinum disposed on said layer of chromium, said chromium layer interacting with said magnetic layer to permit adjustment of the magnetic properties thereof; a barrier layer disposed on said magnetic layer, said barrier layer being a material selected from the group comprising chromium, titanium, tantalum and zirconium; and a wear layer of cobalt oxide disposed on said barrier layer. 
     
     
       3. The invention according to claim 2 wherein said layer of chromium on said surface layer is at least about 1000 Å thick, said magnetic layer is at least about 125 Å thick, said barrier layer is at least 100 Å thick, and said protective layer is at least 250 Å thick. 
     
     
       4. A magnetic recording disc comprising a substrate member of aluminum having a surface layer thereon of an alloy of nickel and phosphorus; a layer of chromium about 2200 Å thick disposed on said surface layer; a magnetic layer of an alloy of cobalt and platinum about 410 Å thick disposed on said chromium layer, the amount of platinum in said magnetic layer being about 3 atomic percent; said chromium layer interacting with said magnetic layer to permit adjustment of the magnetic properties thereof; a barrier layer of chromium about 500 Å thick disposed on said magnetic layer; and a protective layer of cobalt oxide about 420 Å thick disposed on said barrier layer. 
     
     
       5. The invention according to claim 4 wherein said substrate member is about 0.075 inches thick and said surface layer thereon is about 0.0003 inches thick. 
     
     
       6. A magnetic recording disc comprising a substrate member, a layer of chromium disposed said substrate member, a magnetic layer of an alloy of cobalt and platinum containing from about 1 to about 20 atomic percent platinum disposed on said chromium layer, said chromium layer interacting with said magnetic layer to permit adjustment of the magnetic properties thereof, a barrier layer disposed on said magnetic layer, and a wear layer disposed on said barrier layer. 
     
     
       7. The invention according to claim 6 wherein said magnetic layer contains from about 1.5 to about 7 atomic percent platinum. 
     
     
       8. The invention according to claim 6 wherein said wear layer is a material selected from the group comprising the oxides of cobalt, titanium, silicon and aluminum. 
     
     
       9. The invention according to claim 8 wherein said wear layer is cobalt oxide. 
     
     
       10. The invention according to claim 6 wherein said barrier layer is a material selected from the group comprising chromium, titanium, tantalum and zirconium. 
     
     
       11. The invention according to claim 10 wherein said barrier layer is chromium. 
     
     
       12. A magnetic recording disc comprising a substrate member, a layer of chromium disposed on said substrate member, and a magnetic layer of an alloy of cobalt and platinum containing from about 1 to about 20 atomic percent platinum disposed on said chromium layer, said chromium layer interacting with magnetic layer to permit adjustment of the magnetic properties thereof. 
     
     
       13. The invention to according to claim 1 wherein said magnetic layer contains from about 1.5 to about 7 atomic percent platinum. 
     
     
       14. The invention according to claim 1 wherein said magnetic layer contains about 3 atomic percent platinum. 
     
     
       15. The invention according to claim 1 wherein a barrier layer is disposed on said magnetic layer. 
     
     
       16. The invention according to claim 15 wherein said barrier layer is a material selected from the group comprising chromium, titanium, tantalum and zirconium. 
     
     
       17. The invention according to claim 16 wherein said barrier layer is chromium.